It will start OK with air pipe off and immediately refit it to run ok until stopped again but will not idle if started with hose on.

It did have an exchange Air mass / Control unit (Intermotor) form the local dealers in February 2012 and has been fine since.

I suspected it was something to do with me resetting the control unit and somehow not been able to re-adapt it again ?

I have checked the air mass reading at idle using calculations and find it slightly low but ok, the fuel trims and oxygen sensor readings to me bear this out to be ok ?